Chuck



Oct. 27, 1931..

E. J. SVENSON CHUCK Filed 0G;v 5. 1927 @WEA 2 Shouts-Sheet l lfzuerw" jr/zasfi J 5116725071,

' Get. 27, 1931. E. .1. SVENSON CHUCK Filed Oct. 5. 1927 Patented on. 27, 1931 UNITED STATES PATENT OFFICE ERNEST J. SVENHJN, OI BDCKFOBD, ILLINOIS, ASSIGNOR TO SUNDSTRAND MACHINE TUOL 00., O3 BOOKI'ORD, ILLINOIS,

A CORPORATION OF ILLIDIOIS CHUCK Application filed October 5,, 1927. Serial No. 224,033.

My invention relates generally to lathe chucks and more particularly to drive chucks having radially movable work engaging chuck jaws.

The primary object of the invention resides in the provision of a lathe chuck operable quickly and accurately to position and clamp a work piece for rotation about a predetermined axis irrespective of slight irregularities in the surface of the work piece.

Another object is to provide a novel lathe chuck which will obviate the necessit for accurate positioning of the center hole in the Work pieces.

A further object is to provide a chuck having a resiliently pressed cone center and means associated with the chuck jaw operating means operable automatically during the clamping of the chuck jaws to clamp the cone center against longitudinal movement.

Another object is to provide a chuck having a resilienty pressed cone center and means associated with the chuck jaw means erable during the clamping of the chuck aws to urge the center firmly into the center hole of the work piece and to clamp it in such position.

In pursuance of the foregoing objects I aim to provide a lathe chuck having radiall movable chuck jaws mounted on the chuc body, a resilient cone center pin, equalizing means for operating the chuck jaws whereby a work piece may be clamped with an equal force on both sides without a tendency to move said piece, and automatic means 0 erable simultaneously with the clamping o the chuck jaw to clamp the cone center against longitudinal displacement.

Other objects and advantages will become apparent from the following description and from the accompanying drawings in which:

Figure 1 is a fragmentary central sectional view taken longitudinally of a lathe spindle and chuck which embodies the invention.

Fig. 2 is a sectional view of the chuck shown in Fig. 1 taken along the line 9,

Fig. 3 is a front elevational view of the chuck shown in Fig. 1.

Fig. 4 is an enlarged fragmentary view taken along the line 4-4 of Fig. 2.

While the invention is susceptible of various modifications and alternative constructions, I have shown in the drawings and will herein describe in detail the preferred embodiment, but it is to be understood that I do not thereby intend to limit the invention to the specific form disclosed, but intend to cover all modifications and alternative con structions falling within the spirit and scope of the invention as expressed in the appended claims.

In the embodiment chosen for disclosure herein a tubular spindle 5 is shown rotatably mounted in a bearing 6 of a lathe frame 7 and has suitable end thrust bearings 8 interposed between the end of the bearing 6 and an abutment formed by an outwardl extending flange 9 formed at the end of t e spindle 5. An annular guard ring 10 is herein shown surrounding the bearing 8, fastened to the frame 7 by tap screws 11 and extending longitudinally of the spindle to fit around the periphery of the flange 9, thus serving to protect the bearin s 6 and 8.

A main chuc body or head 12 is positioned at the forward end of the spindle 5 coaxial therewith and secured thereto by any preferred means. As herein shown the chuck body '12 has an annular flange 1 extending axially therefrom adapted to surround the periphery of the flange 9 on the spindle 5 thus definitely positioning the chuck body 12 thereon. Suitable fastening means is provided such as tap screws 14 (Fig. 3) extending through bores in the chuck body and engaging the spindle 5.

The end of the chuck body 12 opposite the flange 9 has a pair of work engaging chuck jaws 15 mounted in opposed relation thereon for movement radially thereof. As herein illustrated, the jaws 15 are slidably mounted in radially extending T-slots 16 formed in the forward face 17 of the chuck body.

Means is provided for moving the jaws 15 radially of the chuck body 12 so as to clamp or unclamp a work piece W placed against the face of chuck in contact with an apertured gauge plate 17 attached to the face of the chuck body. In the present embodiment this means comprises a pair of bell crank levers 18, one for each of the jaws 15, mounted 'in the chuck body 12for oscillation in a to engage in transverse slots 22 formed in members 23 mounted in the chuck body for a sliding movement longitudinally of the chuck. The members 23 extend into the bore 5 of the spindle 5 and are pivotally connected at 2A: and 25 to opposite ends of an equalizin bar 26 which is in turn pivotalliy operating the chuck connecte at its midpoint to an'axially sli able member 27 mounted within the spindle and arranged to be reciprocated by any preferred means (not shown). Thus when the member 27 is moved by an actuating means the chuck jaws 15 may be clamped to or unclamped from a work piece according to the direction of movement of the member 27.

To rovide for convenient insertion of chuck aws of different sizes, the'bell cranks 18 are referably arranged so that' they may be easi y moved out of engaglement with the we in the jaws 15. 0 this end the 11 cranks '18 are mounted on removably secured in bores 29 30.

In its preferred form it is contemplated that the invention will be used in connection Eivot pins 28 y set screws with a movable tail stock center (not shown) that work pieces which have previously ha end center holes formed therein will be centered and clamped in the chuck for rotation about the axis determined by the center holes; and that the work will be gauged from a part definitely located with respect to the lathe chuck, for example, the gauge plate 17, thereby making it necessary not only to clam the work for rotation about a redetermine center but also to clamp it wh1 e in firm contact with the gaugeplate.

The provision of an equalizing means for jaws 15 makes it possible to clam a work piece which is located eccentrica y of the c uck by exerting an equal force on each side of the piece without a Y tendency to shift the piece from its eccentric position. Thus when a work piece is positioned eccentrically ofthe chuck due to an eccentric location of the center hole, the piece will be effectively clamped by the 'aws without moving it from the position etermined by the center hole.

In order that such a firm and definite contact may be readily secured between a work piece and the gauge plate 17 irrespective of the depth of the center hole, a cone center pin 31 is provided which is mounted for sliding movement axially of the chuck in a sleeve 32 which is secured in the chuck bod 12. The sleeve 32 has longitudinal slots 2 formed exteriorl thereof in which the members 23 M are slida 1y mounted. A coil spring 33 is mounted in the sleeve 32 so as to abut a rear end wall 34 of the sleeve 32 and the rear end of the center pin, thus servin to urge the center pin 31 outwardly of the c uck and into contact with the work piece W.

In the resent instance the center pin 31 has 8. reduce portion 35 leaving a shoulder 36 thereon which is adapted to abut a gauge plate 17 on the chuck to limit the movement of the pin 31 outwardly thereof, the reduced portion 35 of the pin extending through an aperture 38 formed in the gauge plate.

In the performance of a normal chucking operation of a work piece having end center holes formed therein, the piece is placed between the 'aws 15 with the center hole over the point 0 the cone center, and is moved into firm contact with the auge plate 17" by pres sure exerted on the ot er end of the piece by the tail stock (not shown). The jaws 15 are then clamped upon the piece by moving the member 27 to the left in Fi 1 thus moving the equalizin bar 26, the s ide members 23, and rocking t e bell cranks 18 so as to move the jaws 15 toward the work piece. If it so happens that the center hole is eccentric of the piece, one of the jaws 15 will strike one surface of the work piece before the other, and upon its being stopped, the entire movement of the member 27 will be transmitted to the other of the aws 15 until it also contacts the work piece, whereupon the piece will he clamped between the jaws without moving.

the piece from the eccentric osition deter mined by the position of t e center hole thereln.

Means is provided to fix the jaws and the work piece in the position in which the piece is clamped, this means preferably including the center pin and comprising in the present instance means for giving the center pin 31 an additional thrust into the center hole after the work piece W is clamped between the chuck jaws 15 and to clamp the pin in that position while the jaws remain in clamped position. In the preferred embodiment of the invention this-means is operatively associated with the chuck jaw o crating means and comprises generally a loc ing member d0 slidably mounted in a transverse bore 41 2 formed in the chuck body near the axis thereof. Opposed cam surfaces 42 and 43 are formed on the locking member 40 and the center pin 31 respectively so that upon movement of the member 40 transversely of the chuck 1 through the bore 41 the cam surfaces 42 and 43 will engage and tend to urge the center pin 31 outwardly of the chuck and to clamp it ligizinst the opposite side wall of the sleeve 32.

e engagement of the cam surfaces will of course resist any backward movement of the center pin 31, thus locking the pin in the desired position. In the embodiment illustrated the locking member 40 is normally pressed into operative relation with the center pin 31 I chuck body,

rea ers by means or an expansive coil spring i l at tached to one end of the member and abuttin the outer wall of the chuck.

'I o release the center pin 31 for outward sliding movement before the jaws are clamped, a pin member or other suitable pro ection is ri 'dly attached to the lock mg member an arranged to engage a cam surface 46 (see Fig. 4) on one of the slide members 23 so that when the slide member 23 is moved to unclamp the jaws 15, the member 40 is moved against the action of the spring 44 and the cam surfaces 42 and 43 are disengaged.

Thus it will be apparent that during the initial part of the chucking operation the center pin will be urged into the center hole in the work piece by the force of one spring, which may of course be made of any reasoi able or desirable strength, and that after the work has been clam ed in the jaws the center pin will be urged into the center hole by another force of any desired amount so as to positively center the work piece for rotation about the desired axis It will be apparent that the invention rovides a device having a cone center w ioh is automatically and positively clam ed in its operative position while the chuc jaws are-clamped, and in which a work piece may be quickly and accurately clamped for rotation in its centered position irrespective of slight irregularities in the surface of the work piece.

I claim as m invention: 1. A lathe cluck comprising a rotatable a pair of opposed chuck jaws mounted externally of said body and movable radially thereof, a pair of bell cranks mounted in said body and having one arm of each engaging one of said jaws, and the other arm of each extending radially inwardly of said chuck body, a pair of members mounted for longitudinal slidable movement in said body on opposite sides of the axis thereof, each of said members engaging the radially extending arm of one of said bell cranks, an equalizing bar pivotally connecting said members, an operating means pivoted to said bar midway between said members, a longitudinally slidable center pin mounted in said body axially thereof and between said members, spring means urging said center pin outwardly of said body, spring pressed cam means operable to engage said pin to lock the same against movement, and a cam surface associated with said operating means and operable to engage said cam means to render said cam means inoperative when said chuck jaws are unclamped.

2. In a lathe chuck having a pair of radially movable opposed jaws and a resiliently pressed cone center, means for moving said jaws comprising a pair of bell crank levers mounted in said chuck and each having one arm engagin one of said jaws, a link connected to each of the other arms of said bell cranks and extending longitudinally of said chuck, a her having one of its ends pivotally connected to each of in predetermined axial relation to the chick,

jaws for clamping work mounted on said can ter and operating means for said jaws, of means operable by said operating means effective to urge said cone center into firm contact with a work piece durin the clamping of said piece in said jaws an then to clamp said cone center in such contact.

4. Adathe chuck having chuck, jaws, a center pine movable lon itudinally of the chuck independently of the jaws when said jaws .are .unclamped, resilient means for pressing said pin outwardly of said chuck, means for clamping said aws on a work piece, and means associated with the last said means and operable thereby for clamping said center pin against longitudinal displacement.

5. A lathe chuck having longitudinally movable center pin, resilient means for pressin said pin toward the work piece, a pair 0? radially movable opposed chuck aws, equalizing means for clamping said jaws upon a work piece, acam member for urging said center pin outwardly of said chuck and for clamping said pin in such position, said member being mounted transversely within said chuck and adjacent said center pin, resilient means urging said cam member into operative relation with said center pin, and means operable to control the operation of said cam member.

6. In a lathe chuck, the combination of radially movable chuck jaws, equalizing operating means for said jaws, a spring pressed center pin, locking means for said. center pin, chuck jaw operating means to control the operation of said locking means according to the position of said chuck jaws.

7. In a lathe chuck, the combination, oi radially movable chuck jaws, equalizing operating means therefor, a yieldable cone center, means for locking said center against longitudinal displacement, and controlineaus for said locking means associated with and operable by said chuck jaw operating means.

8. A lathe chuck comprising a rotatable chuck body, a pair of opposed chuck jaws mounted externally of said body and n1ovable radially thereof, a pair of bell cranks mounted in said body and having one arm of said links, means pivot- 1 ally connected to the center of said bar :tor

and means associated with said I said bell cranks, an equalizing bar means mounted each engaging one of said jaws and the other arm of each extending from its pivot radially inwardly of said chuck body, a pair of members mounted for longitudinal slidable movement in said body on op osite sides of the axis thereof, each of said members engaging the radially extending arm of one of pivotally crating tween connecting said members, and 0 means pivoted to said bar midway said members.

9. The combination with a lathe chuck having a resiliently pressed cone center movable longitudinally of the chuck, ofrneans for locking said center against longitudinal displacement in any position lying within its normal ran e of movement, and a member 1011 itudina ly slidable within said chuck an operable to control said locking means.

10. A lathe chuck comprising, in combination, a chuck body, an apertured gauge plate mounted on said body, a yieldable cone center reciprocably mounted in said body and adapted to extend through said aperture,

means operable to lock said center against,

displacement, radially movable chuck jaws mounted on said body, equalizing operating means for said jaws, and means associated with said chuck jaw operating means for controlling the operation of said locking means. 5

11. A lathe chuck comprising, in combination, a chuck body, a cone center mounted for longitudinal movement therein, chuck jaws, equalizing means for clamping said jaws on a work piece, and automatic locking means operable simultaneously with the clamping of said jaws to lock said cone center against longitudinal displacement.

12. A lathe chuck comprising a chuck body, thereon for engaging a work piece to drive the same, an apertured gauge platemounted on the face of said body, a yieldable cone center adapted to be pressed through the aperture in said plate and into contact with a work piece, and cam means for locking said cone center against longitudinal displacement.

13. A lathe chuck comprising, a chuck body, radially movable chuck jaws mounted therein, equalizing operating means for said jaws whereby a work piece may be clamped on the face of said chuck eccentrically thereof, and means for securing said jaws against movement from such eccentric position operable after the clamping of the workpiece therein.

14'. The combination with a lathe chuck having a yieldable cone center, of locking means associated with said center and operable to urge said center slightly forward and secure it against longitudinal displacement,

and a member mounted for movement longitudinally of said chuck body and operable to control said locking means.

15. In a lathe chuck adapted to clamp work located eccentricall of the chuck, the combination of a chuck body, opposed chuck jaws mounted thereon, a member mounted for movement longitudinally of said chuck, an equalizing bar having its midpoint pivotally attached to said member, means connecting the ends of said bar to the chuck jaws operable by longitudinal movement of said member to clamp said jaws, and means operable after the clamping of the jaws for securing said jaws and the work against movement laterally of-the chuck, said means including a longitudinal movable center pin mounted on said chuck body and adapted to engage the work.

16. A lathe chuck comprising, in combination, a rotatable chuck body, clamping means movable radially of said body to form a drivmg connection with a work piece positioned eccentrically of the chuck body for rotating the work piece with said chuck body, means movable axially of said bod independently of said clamping means whi e said clampin means is unclamped so as to ermit a wor piece to be positioned in de nite predetermined axial relation to said chuck body and operable to position such a work piece for rotation about a definite predetermined axis in said work piece, means for clamping said last mentioned means in fixed axial position, and means operable to actuate both of said clamping means in timed relation to each. other.

17. A chuck having, in combination, a body, chuck jaws'movably mounted thereon, a

cone center slidable axially on said body, re- 7 silient means normally urging said cone center toward a work piece mounted between said jaws, and means for clamping sajid center in its operative position comprising a member slidable transversely of said center,

faces engageable by moving said member, said surfaces being inclined so that when said member clampsthe center it tends to move the center longitudinally toward the work.

19. A chuck comprising, in combination, a chuck body, a gauge abutment on said body against which one end of a work piece may be positioned, chuck jaws mounted on said body, a center slidable axially of said body and arranged to engfie the end ofthe work I iece to center it, u 'zing operating means or clamping said jaws onto the centered work piece, and means operable to lock said 5 center against the end of the work piece.

20. A chuck havin in combination, a body, chuck jaws movagly mounted thereon, a center slidable axially on said body and arranged to center a work piece, means for 10 clam ing said jaws onto the work piece without 'sturbin the centered position thereof, an abutment or the ad 'acent end of the work, resilient means norma y urgin said center against a work piece mounted tween said 15 jaws and with one end against said abutment, and means for clamping said center in its I i work eiiggglilxi positlon.

21. having, in combination, a

chuck jaws movably mounted thereon,

29 equa zin means for clampin said jaws on a wor piece, a center slidab e axially on said body and'arranged to center the work piece, and means for clamping said center in its operative position comprising an adjust- 25 ablemember, said center and member having co nding interengaging surfaces engages Is by moving said member, said suraces being incline transversely and longitudinally of the center so that when said memher is wedged against the center it tends to move the center longitudinally toward the or a In testimony whereof, I have hereunto affixed my signature.

. I ERNEST J. SVENSON. 

